1. Field of the Invention
The present invention generally relates to a gap-forming device and more particularly, to a gap-forming sheet used for bonding a plurality of substrates or flat electrodes through predetermined intervals therebetween by pressing and heating the substrates, with gap members and bonding/fixing members being disposed between the substrates, and a method of manufacturing the gap-forming sheet of the above described type, and also, a method of joining flat electrodes by using said gap-forming sheet.
Conventionally, in a flat-face type display device utilizing an electron beam, it has been attempted to effect lamination of control electrodes by joining a plurality of flat electron beam control electrodes through a predetermined interval at high accuracy in a state electrically insulated from each other in order to reduce thickness of the device. In the arrangement as referred to above, the electron beam emitted from the cathode is deflected in vertical and horizontal directions by the laminated control electrodes so as to illuminate fluorescent materials formed at predetermined positions on a screen for displaying images. In this case, the intervals to be formed between the respective electrode substrates must be uniform over the entire surface of the electrode, with curving and undulation being suppressed to minimum, while a perfectly insulated state is maintained.
Referring to the drawings, one example of the electrode construction in the conventional flat-face type display device referred to above will be described hereinbelow.
FIG. 6(a) is a side sectional diagram showing a general construction of a conventional flat laminated electrodes, and FIGS. 6(b) and 6(c) are also side sectional diagrams for explaining a manufacturing method of the conventional flat laminated electrodes.
As shown in FIG. 6(a), the conventional laminated electrodes include for example, four flat electrodes 4a to 4d, and spacing or gap members 2 and glass members 13 for bonding disposed at high positional accuracy between the respective substrates as illustrated.
For manufacturing the known laminated electrodes as referred to above, the gap members 2 having uniform thickness for maintaining a proper interval between the flat electrodes 4a and 4b and the bonding glass members 13 for joining said electrodes 4a and 4b are first disposed on the flat electrode 4a as shown in FIG. 6(b). For the gap members 2, a rod material of glass or ceramics, etc. which is a heat resistant insulator with a high melting point is employed, while, for the bonding glass members 13, an insulator such as a glass rod material with a low melting point, etc. may be used. Thereafter, as shown in FIG. 6(c), the flat electrodes 4b, 4c and 4d prepared in the similar manner are overlapped on the flat electrode 4a through accurate positioning, whereby the plurality of flat electrodes 4a to 4d are piled one upon another, with the gap members 2 and the joining glass materials 13 held therebetween. Then, by applying a uniform depressing force over the entire surface of the flat electrodes 4a to 4d so that said electrodes 4a to 4d may not be deformed by heat during processing, baking is effected at a temperature above the melting point of the bonding glass members 13. By such baking, the bonding glass members 13 are melted for joining the flat electrodes 4a and 4b located at the upper and lower portions, while the gaps can be formed by the thickness of the gap members 2, and ultimately, the laminated electrodes as shown in FIG. 6(a) are obtained for application as the electron beam control electrode of the flat face display device.
In the manufacturing method of the conventional laminated electrodes as described so far, however, it is required to repeatedly arrange the plurality of small sized gap members and the bonding glass members 13 on the flat electrode substrates 4a to 4c through accurate positioning, and therefore, not only high accuracy is necessary for the processing, but working time tends to become longer, with a consequent reduction in the mass productivity. Moreover, since the above arranging work must be repeatedly effected on the laminated substrates, dust and soiling substances tend to adhere onto the surfaces of the substrates, thus resulting in a large factor for lowering yield.
2. Description of the Prior Art